Air damper control for heating and cooling systems



Aug' 17, 1954 L. H. GILLICK ETAL 2,686,661

AIR DAMPER CONTROL RoR HEATING AND cooLING SYSTEMS Filed April 5. 1949 2 SheetsSheet 1 Aug- 17, 1954 L. H. GILLlcK ETAL 2,686,661

AIR DAMPER CONTROL FOR HEATING AND COOLING SYSTEMS Filed April 5, 1949 2 Sheets-Sheet 2 M1-mm sae-Nalo Patented Aug. 17, 1954 AIR DAMPER CONTROL FOR HEATING AND COOLING SYSTEMS Laurance H. Gillick, Evanston, and Timothy J. Lehane, North Riverside, Ill., assignors to Vapor Heating Corporation, Chicago, Ill., a corporation of Delaware Application April 5, 1949, Serial No. 85,562

2 Claims.

This invention relates generally to improvements in air conditioning systems and relates particularly to a control system in which air dampers are controlled to provide maximum fresh air for all conditions of ambient temperature.

In systems for controlling the temperature of enclosures it is desirable at all times to introduce as much fresh air into the enclosed space as is consistent with maintaining the loads on the heating and cooling apparatus at a minimum. Thus at times when the outside temperature is very low, for example, below 0 F., it is desirable to introduce 25 percent of fresh air into the space while recirculating '75 percent of the air therein so that the demand on the heating system is not too great. ture is greater than 80 F. it is also desirable to maintain like proportions of fresh and recirculated air, in order that the demand on the cooling system is not too great.

` A principal object of the invention is to introduce a maximum amount of fresh air into the enclosed space between two extremes of ambient temperature and to recirculate a maximum amount of air within the enclosed space when such recirculation of air is required to relieve the heating load or the cooling load imposed on the system.

A second object comprehends the provision of fioor and overhead heating when the temperature of the enclosure is below a certain intermediate value and the provision of overhead heating only when the temperature of the enclosure is above a certain intermediate value and below a certain maximum value.

Still another object is to provide for suitably tempering (heating and/or cooling) the air within the space when the temperature of the space reached certain predetermined values.

, Another Objectis to provide blower and exhaust fans which are operable at different speedsaccording to the inside temperature` requirements in relation to the outside temperature,` and/or inside maximum temperature.

The invention is illustrated in certain preferred embodiments, in the accompanying drawings wherein:

` Fig. 1 is a schematiclongitudinal cross section taken through a railway car having `the present invention embodied therein; and

Fig. 2 is a circuit diagram showing the electrical circuits controlling the apparatus of Fig. 1.

Referring to Fig. l of the drawings, a railway vehicle it is indicated schematically in longituj,

Likewise, when the outside temperal dinal cross section, to which the heating and air conditioning system according to the present invention is applied. It should be understood, however, that the invention is not coniined to a railway car, but is equally applicable to any enclosed space.

The car lil is supplied with heat by means of a floor radiator il which is supplied with heating medium, such as steam, from a main supply line i2, the supply of steam to the iioor radiator Il being under the control of a solenoid operated flow valve I3 and an additional solenoid operated admission valve lli, the condensate leaving the floor radiator ll by means of outlet pipe I6.

The car iii is provided with an overhead duct il which has an entrance opening I8 thereto for a supply of fresh air. The duct il is also provided with a plurality of outlets I9 whereby heated and/or cooled air is supplied to the interior of the car. The duct il is also formed with a return duct 2l. In order to insure oirculation of air through the car Hl, an exhaust fan 22 is provided in the return duct 2l, the duct il being additionally provided with a blower 23 for circulating both fresh and recirculated air.

The duct I'i also has situated therein an overhead air heater 24 which is supplied with steam from a supply line 2'6, the supply of steam to this heater being under the control of a solenoid operated flow valve 2l and a solenoid operated valve 28, the condensate discharging through pipe 29.

Under certain condition of opera-tion, and also when the temperature outside the car rises above a certain value, the air supplied to the car I6 by the duct il is cooled. This is accomplished by means of a cooler 3| which is supplied with coolant or refrigerant by a mechanically operated refrigerator system 32 including 4a motor-com-- presser unit 33, under the control of a solenoid operated switch 34, a condenser 36 and coolant reservoir 3l. The supply of coolant to the cooler 3i is also under the control of an electrically' operated valve 38. This valve is positioned in a supply line 39, the spent coolant being returned to the compressor unit 33 by a suction pipe t! Under certain conditions of operation, as will be described in more detail, the car I il is provided with 90 percent of fresh air, supplied to the car at the opening I8, and 10 percent of recirculated air fromthe interior of the car, the

amount of fresh air and the amount of the re-` circulated air being under the control of a damper valve i2 which is actuated by an electrically energized device, for example a solenoid 43 and linkbe supplied by the floor radiators i i, the dal supplied to the car andY l percent of the air within the car is re-circulated, 90 percent of the air from within the car being vented to the outside atmosphere through an exit port It. Under other conditions of operation, 75 percent ci the air within the car lil will be recirculated, and percent of freshair will be brought in from the outside of the car, the damper valve @2 under such conditions oi operation taking the position as shown in the dotted line in Fig. i.

Referring now to Fig. 2 ot the. means are provided for maintaining the damper it n the dotted Vline position as shown in Fig. i, whereby to introduce 25 percent of fresh air into the car and to re-circulater' percent of the air, and

0?. and the temperature in the return duct isV below 78 F., heat at the floor of the ear il.

ner 42 will be in the dotted line position shown in haust fan 22 are operated at low speed.

this condition the blower 23 and the exhaust fanV dition of operation, the solenoid t3 is deener gized, the winding thereof being in an open cirn cuit which includes the positive line 52, Va con ductor 77, an open contactor Eil ci a relay 'i9 interposed in circuit with the conductor "i'i, and the main negative line 54.

Under conditions when the outside temperature is below 0 F., the blower 23 and the eX- T nder 22 are ina closed circuit leading from positive line 52 through conductor Si, an adjustable resistor S72 connected therein and a conductor 83 to the negative bus 53.

The circuits thus far describedarc eective when the outside temperature is below 6 E'. The system, according to the Vpresent invention, includes both floor heat and overhead heat, both ofv which areV effective during the normal heating cycle. The floor radiators are made ineffectivewhen the outside temperature rises above 56 F. At this time andrthroughout anyadditional rise in temperature, cooling is ina-de available within the car it by the energization of master relay iid, provided that the interior ternperature is such as to requireY cooling. if no Y cooling is required within the car it the over- Fig'. 1 to give 75 percent of 're-circulated air and 25- percent oi fresh air, and the blower 23 and Vtheexhaust fan '22 will operate at slow speed.

The overhead heater `will also supply ce circulated through the duct l? and past 'the overhead openings is.' Under this condition of operationa winding 5t olthe floor heat now valve I3 is deenergized, the winding 5t being in parallelV with .thersolenoid of relay i5@ of the compressor 33 andremaining deenergized with the valve i3 open until the'outside temperatureY rises to .50 at thermostat l2i and the temperature in the return duct rises to 76 E'. At this tiine the va i3 will close, thus shutting off the new or" ste to the admission valve It of the floor radiator.

The floor radiator admission valve it is nor- Y nially held open by a spring its. Consequently the valve is held open to supplyrsteain to the iiooi` radiators Il as long as the outside temperature remains below F. and the temperature within thefcar is less than 78 F.Y However, when the Ytemperature within the car reaches 78 F.,'the l energizing circuit iorrelay iii is Toy-passed around il interposed'is in a closed circuit which includes Ythe bus '52, a conductor 'l2 and a closed contacto'r tjof `a relay 'it which is adapted to be 'energized when the temperature in the. return duct 2i is'below a certain value, which in the embodiment shown is 78 F.

When the'outside temperature is below 6 thel damper valve .12 isrin Vthe dotted line posi-* tion shown vin Fig. l to provide for 75 percent oi headheating system willcontinue to operate to maintain the proper temperature without the need for heat to be supplied by the'ioor radiators l l. 'Y l K The circuits for controlling the heating and air conditioning system according to the present invent-ion include a holding or stick circuit which re-circulated air and the admission into the car Y VlilV of 25 percent of; fresh aux. Under .thisconN effective.

responds to certain conditions in order to be made The first of these conditions is that the outside temperature is above WF. and the second condition is that the return duct 'tenir perature must'be below 78 F. When the outside temperature stands between 0 l?. andrless than 50 EL. and that the temperatureV in the 'return duct Zlis below 78 F., the following thefwinding B7 of a relayrvt, and'rthence through a resistor Se and a conductor di to the negative bus line 53. The energizing ofthe relay (it closes a circuit which includes the positive line 52, a conductorV 92, Va contactor t3 ci the relay t8 and a conductor Sil which taps the mid-point of the variable resistor 2 thereby'increasing the operation of the blowers Yand the exhaust fan 22 to an intermediate speed, and thence through the blower 23 and the exhaust fan 22 through a conductor t3 to the negative bus` 53. i3 and the exhaustV fan 22are connected in )parallelso that both will operate at the saine speed.

An additional circuit is closed upon energization of the relay 83, said circuit including the positive line 52, a normally closed switch 95 'in lthe relay la which is maintained energized so long as the thermostatV E03 in the return duct 2l.

It will Ybe observed that the blower Y see also Fig. 1, is below 78 F. As long as the temperature in the return duct 2| is below 18 F., a circuit is made through a winding |04 of the relay 14, a conductor |06, and resistors |01 and |08 with which the winding I 04 is in circuit. The closing of the relay 19 energizes the winding 16 of the solenoid actuator 43, thus moving the damper valve 42 to the full line position shown in Fig. l, the damper valve 42 then being in position to admit 90 percent of fresh air and to recirculate percent of the air within the car I0.

Energization of the relays 88 and 14 controls a stick circuit for energizing a relay |09. When the relays 88 and 14 are thus energized, under the conditions as described above, the stick circuit thus made includes a conductor III branching from the conductor 91, a winding I I2 of the relay |09, thence through a conductor I3 which is connected to the lead 90, the circuit then being completed through the contactor 99 of the relay 88, the line |0| and the contacter |02 of the relay 14. The energization of the relay |09 closes another stick circuit which includes conductor II4 branching from the lead II, thence through the closed contacter HB of the relay |09 to the negative bus 53 through a conductor II1.

From the foregoing description it will be ap parent that when the temperature outside the car is between 0 F. and 50 F. the system will operate to give 90 percent of fresh air, the air so supplied by the blower 23 and the exhaust fan 22 operating at intermediate speed, at the same time both oor heat and overhead duct heating being supplied with steam through the ow valves I3 and 21 and theiioor radiator admission valve I4 and the overhead heat valve 28 as before; the circuits for maintaining conditions of the valves I3, I4, 21, and 28 remaining thesame as though the outside temperature were at 0 F. or less.

Under the condition when the ambient outside the car I0 is greater than 50 F. the system is so arranged that the heating vapor supplied to the floor radiator I| is out off by the iioor valve I4, heat being supplied to the interior of the car I0 through the overheadheater 24 under the control of the overhead heater valve 28, provided that the return duct temperature remains less than 80 F. Under this condition of operation, when` the outside temperature is greater than 50 F., the blower 23 and the exhaust fan 22 will operate at full speed, the resistor 02 being shunted out of circuit with the `blower 23 and the fan 22.

When the outside temperature reaches 50 F., a winding I IB of the master relay 64 will `be enern gized, the circuit leading from the positive line 52 through the coil IIB, and a conductor H3 including an outside thermostat I2| which closes when the outside temperature rises to 50 F.

When the relay 64 is thus energized, an additional ing cooling thermostat |26`positioned in the re turn duct 2|, and a conductor |21 to the main negative line 54.

The energization of the relay 64, which takes place when the `outside temperature rises to 50 F., also causes the blower 23 and the exhaust fan` 22 toV operate as full speed, at full supply potential across the supply line 52, 53. Whenthe relay 64 is energized, a circuit is made leading from positive line 52 through a closed contactor I 23 of the relay 64, a conductor |29, a closed contactor |3| of the relay |09, a conductor |32 joining the conductor 8| and thence through the blowers 23 and the exhaust fan 22 and the conductor 83 to the negative bus line 53.

As long as the temperature of the return duct 2| is below 78 F. the relay 14 remains energized, the coil |04 of the relay being in circuit with the conductor |06 across the supply line 52, 54. The relay B4 controls the operation of the floor heat relay 3! and through it controls the floor heat valve 4. When the outside temperature reaches F. the relay 64 is energized which condition opens contact |34 thereof and deenergizes the relay 6|, the circuit for the relay EI including positive line 52, conductor |33, contactor |34 (now open because the relay E4 is energized), winding |36 of the relay 6I and closed contactor 31 of the relay 14, the latter of which remains energized While the return duct is below 78 F. When `the relay 5| is thus de-energized, the winding 51 of the floor heat valve I4 will be energized and the valve I 4 will close thus cutting on? the supply of steam to the radiators When the outside temperature moves below 50 F. and the temperature of the return duct 2| is less than '18 F., the circuit for energizing relay 6| is closed through de-energized closed contact |34 of relay 04 and energized closed contact |31 of relay 14. Under such conditions the temperature at the floor thermostat |38 will be below 78 F. Consequently the relay 6| 'will be energized open and the iioor heat valve will remain open under the inuence of spring Illa, but when the temperature within the car again reaches 18 F .while the outside temperature remains below 50 F., the supply of electric current to coil |33 of relay 6I will be cut orf by the opening of contact I 31 of relay 14 and thereby result in closing relay 6I to energize iioor heat valve |4 closed. The floor heat thermostat |38 is provided with an auxiliary heater I 30 which is energized and in a circuit including conductors I4I, |42, |42a and contactor |43 of the relay 14.`

Thus, when the return duct thermostat |013 controlling the overhead heat is calling for heat, the relay 14 will be energized and the contacter |43 will be opened. Auxiliary heat will be removed from the oor heat thermostat 38, but as soon as said return duct thermostat |03 is satisiied the contacter |43 will close and the thermo- I stat |38 will receive suicient auxiliary heat to thermostat is calling for heat, the relay 6| will be cie-energized closed by the functioning of thermostat |38 and the radiator valve I4 will be energized closed to shut 01T the floor heat.

However, iloor heat will not be supplied to the `radiators j|| since the` flow of steam to the floor radiators I| is also under the control of the flow valve |3 which isiclosed when its coil 55 is energized. The temperature in the return duct `2| isadaptedto control the now valve I3 and to the teiripera'ture'` in. the return'. duct 2|] reaches 75 F.' and the ambient is above 50 F. a circuit is made which includes a conductor |114, contactors |45; acoil |41 of the relay 68, a'cooling pilot thermostat Hi8-and alead M3 tothe negative bus 53. The energization of the relay @s closes the circuit'V through'. the contactor 53 of the relayY inigthecontact'or Slotv the relay 68, the

lead t@ and the coil 5t of the flow Valve i3, thus closi .g the valve I3. A'- parallel ,circuit is made 'it this time through -a coil |51 of the solenoidV VVcooling pilot thermostat |58 are respectively provided with auxiliary heaters |52, |53 and |513 whichhave a niaxium variation of 6 F. and are adjustable by a variable resistor |56. Auxiliary heater |52 is-in a circuit which comprise adjust" able resistor |58, a conductor it?, la resistor ii'u and the conductor |21. Auxiliary heater |53 is in a circuit which includes the adjustable Vresistor |56, a conductor |58, a resistor |59', and a lead,

iii. TheA auxiliary heater l is in a circuit including the adjustable resistor |56, lead |58, a resistor |62, and'avlead |63.

It will be seen from thcfforegoing that there is Va range of temperatures within'the carfi during whichrange both overhead heat and cooling will be had. This range of temperatures in i the return duct 2|is from 76 F. to '78 F. As explained, the relay GB' willV be energizedwhen the temperature inthe return duct 2| reaches .76 F. to start thecornpressor 33, the cooling pilot thermostat |48 controllingY the relay 88. The relayV ill is deenergized when the temperature in the return duct 2|v reaches 78 F., the thermostat ViW'shorting out' the Vcoil 5811:. When the temperature inthe return duct 2| reaches 78 F. Y the circuitrforlenergizing the relay 19 is opened and the solenoid l is deenergized, thus moving the ,damper :32 to the ,dotted line position seen in Fig. 1` to provide for 75 percent of re-circulated airand 25 percent of fresh air. When the tern perature in therret'urn duct reaches '78 Roverhead heatffrorn the overhead heater Y2t is cut oisince Vthe deenergization of the relay 'i4 will open the contactor i3 and'deenergize the wind- Y ing 'i i of the valve 28'. At this time the air, moving past the evaporator 3| will cool the car il).

VWhen the'temperature in the return duct 2| andthe ear ii)V reaches 80Vo F. both relays |88 and la willY be deenergized, the cooling re-circulating control thermostat |25 shorting out the 'g windingl i2 of the relay |89 to reducethe operating speedfof the fan 22 and blower 23 and also Y snorting out the winding of relay i8 so as to de- Venergize the damper solenoid 43 and thereby permit the damper'dZ to assume the dotted line positionV in Fig; l. VThe short circuit so made leads from positive'line 52` through conductor 5?, closed switchl, conductor conductor |22, closed contactor |23, conductor |2ll, the cooling recirculation Ythermostat |26, conductors H3 and 88 through closed Contact 990i relay B8, and

. thence'through conductor im and closed contact Y The de-Vi energization ofA therelay |39 opens the contacter |82y oi" relay l to the negative busV 53.

|31', whichA when: closed" shorts outthe resistor relay controllable by Vthe last mer 8i Y 82 controlling the speed of! the blowers23f and the eXhaust'fan'ZZ.

at intermediate speed; only a portion of the re sister Bbeing in circuit with the fanand blowers, the circuit thereto then including the conductor s2, clcsedcont-actor 93, lead 94, part'of the resister 82 and conductors 8|. and 83. The de- Venrergization of relay 18 opens contact 'i8 and therefore deenergizes the solenoid 25, whereby the damper is moved by spring a5 to the dotted line position of Fig. lrfor delivery of 75 percent o re-circulated-air and 25 percent offresh air through the cooler 3|.

It Vwiil Ybe thusseenV that a novel andY seful form or a combined heating andair cooling sys`- in the space within narrow limits. The system according to the present invention is cterized hy-the provision of maximum amount of' fresh air 'when the outside temper-- ature, within the space within narr iv limits.'V

to Vreduire the recirculation ofthe' pre .iously treated air. Y

Whilethe invefntion,.-ha,s been described in aclcoroanee with a pre embodiment, its scope 'pten'deflto be limited in ter or" the"ernclaim: t

i. A' system for-,supplying tempered air'to an encloscdspace to maintain a'desired temperature therein,` comprising, in combination, an eleo trice-ily operated blower communicating with theV enclosedY space and with the outside Vai'in'icsphere for deiivering a stream of air into saidV enclosed space, electrically operated exhaust ian connested in parallel with blower and o erable to withdraw air irorn the enclosed space and` discharging the saine into the outside atmosphere, means for altering the temperature of the air stream delivered by said blower, a damper oper-V able to vary the proportions of external air and recireulated air delivered into the enclosed andrelectrical means for actuating saidY damper, means including a therrhestat responsive to the temperature of the enclosed space and-'a relay control thereby for increasing andA decreasing the ei'ectivenessV of said temperature'alterinrf. means, means including' a secondV thermostat responsive to a predetermined outside temperatureV and a relay control thereby for varying the opera-ting speeds for said blower Vand said ezhaust fan, a ioned reiay and adapted to control the energiz'ation of said damper may be altered to reduce the temperature Y 'altering load on the system Vhy varying the proportion of'- recirculated air and fresh air in relation tothe temperature requirements of the en closed space, a master relay, a thirdrtherrnostata relay cooperating Ywith a closedcontaot of said' master relay for closing an energizing circuit to further alter the operating speedsrof said; blower When` the contactorY i3 I is open the fan` 22'a'nd the'blowerl 23 will operate .it shown nor othcrwisethar. by the terms 2. A system for supplying tempered air to an enclosed space according to claim 1 characterized in that a fourth thermostat is provided for controlling the last mentioned relay effective to alter the operating speeds of said blower and fan, the said fourth thermostat being set to function at a predetermined inside `temperature to open the last mentioned energizing circuit through said blower and said fan.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Bulkeley Mar. 6, 1934 Atherton Aug. .11, 1936 Madden Oct. 12, 1937 Seid Jan. L24, 1939 Haines Oct. 24, 1939 Parks et a1. Dec. 5, 1939 Euwer May 21, 1940 

